As an antivibration device such as an engine mount which supports a vibration source such as an automobile engine in a state where vibrations of the vibration source are not transmitted to a vehicle body side, there has been known a liquid-sealed antivibration device which includes a first mounting part, a second mounting part having a cylindrical shape, an antivibration base body connecting these mounting parts and is formed of a rubber-like elastic body, a diaphragm which is mounted on the second mounting part so as to form a liquid sealed chamber between the diaphragm and the antivibration base body, a partition body which partitions the liquid sealed chamber into a first liquid chamber on an antivibration base body side and a second liquid chamber on a diaphragm side, and an orifice flow passage which allows both liquid chambers to be communicated with each other. The liquid-sealed antivibration device is configured to perform a vibration damping function and a vibration insulation function due to a liquid column resonance action brought about by the liquid flow in the orifice flow passage and a vibration control effect brought about by the antivibration base body.
For example, in the following patent documents 1, 2, there is disclosed an engine mount where the above-mentioned partition body is constituted of an annular orifice forming member which is provided inside a peripheral wall portion of the second mounting part and forms an orifice flow passage, an elastic membrane which partitions the inside of the orifice forming member into a first liquid chamber and a second liquid chamber, and a pair of displacement restricting members which restricts a displacement amount of the elastic membrane from both sides of membrane surfaces of the elastic membrane.